The present invention pertains to optical target detection and more particularly to alignment of relatively small transmit and receive fuze light beams.
Present day optical fuze systems rely on mechanical alignment of separate transmit and receive fuze light beams for target detection. Since in separate aperture optical systems both fields of view are not coincident, alignment between receiver and transmitter beams over all operating regions is critical. One such system which requires mechanical alignment of optical fibers is shown in U.S. Pat. No. 4,518,255, issued on May 21, 1985 to Ranier Zuleeg and having McDonnell Douglas Corporation as the assignee.
Relatively small beams require tight tolerances in the alignment process. Also, aerosol backscatter performance degradation is directly related to the size of the fuze beams. Smaller fuze beams illuminate less aerosol and produce less aerosol backscatter. If the fuze light beams are enlarged to provide for easier alignment tolerances, an unsatisfactory fuze beam size for adequate aerosol rejection is the result.
Accordingly, it is an object of the present invention to provide an optical target detector providing for accurate alignment of receive and transmit beams while providing a high level of aerosol backscatter rejection.